Indoor cultivation of fruits, vegetables, flowers and ornamental plants is an increasingly popular method of producing living plants, whether for the horticulturist, hobbyist or professional nursery operator. Lighting conditions including illumination uniformity and proximity of the radiation source to plants associated with such cultivation are known to have important effects on the quality and abundance of plants. Consequently, efforts have been made to provide for the uniform illumination of growing plants in greenhouses or the like. Particular problems are encountered in at least two situations, including: lighting non-uniformities at different distances from a lighting source may cause plants to be exposed to such non-uniformities as the plants grown in height; illumination non-uniform (overlap and/or gap) areas that result from collecting together a plurality of lighting sources having round or oval shaped areas of illumination; loss in lighting efficiencies when different light bulbs having different radiant arc locations, relative to a fixed light bulb mounting socket, are mounted within a lighting system with the radiant arc at other-than the focal point of a lighting system reflector; and, a loss of convenient operating space between the top of plants and the lighting system as plants grow in height.
Lighting reflectors are available typically with a horizontal bulb mounting socket, below which is a flared out a generally uniform frustoconically shaped reflector, optionally having below a further downwardly and outwardly extending portion terminating in an almost cylindrical lip. Such reflectors tend to reflect the light downwardly in a flood angle from about 65 degree(s) to about 75 degree(s) which requires the reflector to be located only a few feet, e.g. 3 to 4 feet, above the plants. As such, the lighting uniformity available from such a reflector is adversely affected when the reflector is adjusted in height to avoid the situation when plants grow into undesirably close proximity the reflector. Inconveniently, lighting reflectors may be adjusted upwards as plants grow in height. Furthermore, cultivation of plants illuminated by such a reflector hood is awkward because of the limited free movement possible by a horticulturists beneath a hood located only a few feet above plants.
In view of the foregoing, it is believed to be advantageous to provide a horticulture lighting system for providing uniform illumination to a plant area without overlapping or non-illuminated areas. Another shortcoming not addressed in the prior art is the inability to accommodate the growing height dimensions needed by large plants as well as operating space needed by horticulturists. A further shortcoming not addressed in the industry is the ability to readily change lighting bulbs from one type to another without sacrificing uniformity or efficiency.